5 ms·

It is really disturbing to look at an article like this and not see a single mention of the HUGE amount of fresh water being dumped into the ocean in order for

It is really disturbing to look at an article like this and not see a single mention of the HUGE amount of fresh water being dumped into the ocean in order for these locks to function.

fennecfoxen 10y ago
As an interested party, could you indicate some decent, accessible resources on the topic? A casual Google search for things like 'panama canal fresh water' isn't turning up much that looks particularly authoritative or comprehensive.
- timthelion 10y ago
  https://en.wikipedia.org/wiki/Panama_Canal#Water_issues https://en.wikipedia.org/wiki/Panama_Canal#Water_issues
  - fennecfoxen 10y ago
    > https://en.wikipedia.org/wiki/Panama_Canal#Water_issues https://en.wikipedia.org/wiki/Panama_Canal#Water_issues That's written from the perspective of 'water shortages during the dry season are one reason they built new locks, which can reuse water'. It doesn't begin to address any impact on the oceans.
quantumhobbit 10y ago
Presumably the old locks were dumping slightly less huge amount of fresh water. Has the ratio of fresh water to cargo improved or gotten worse with upgrade? Maybe there is an opportunity to make use of osmotic power https://en.m.wikipedia.org/wiki/Osmotic_power https://en.m.wikipedia.org/wiki/Osmotic_power with the locks.
- dalke 10y ago
  The new locks use water saving basins. https://en.wikipedia.org/wiki/Panama_Canal_expansion_project#Water_saving_basins https://en.wikipedia.org/wiki/Panama_Canal_expansion_project... According to http://www.marinelink.com/news/watersaving-panama-canal404727.aspx http://www.marinelink.com/news/watersaving-panama-canal40472... : > And each [pond] utilizes state-of-the art technology which allows the Canal to reuse 60 percent of the water used per lockage, saving 7 percent more than the existing locks do. Also, the current system requires no power, except to open and close valves. It is expensive to pump water uphill, because water is heavy.
dublinben 10y ago
Luckily fresh water is a renewable resource.
onion2k 10y ago
If the canal weren't there then the rain water that fills the lake that supplies the locks would just run in to the ocean anyway. The only difference the canal makes is when the water gets to the ocean - it gets stored in a lake for a while first. Does that really have an impact? Why?
chiph 10y ago
The new locks have nine water re-utilization basins to minimize lost water. Not because it's potable, but because if the lakes run dry, commerce stops.
jcranmer 10y ago
A single downward lock cycle uses 100,000m³. About 35-40 ships per day transit the canal, so a single day wastes about 4,000,000m³ of water. The Mississippi River discharges about 17,000m³ a second. Each day, that river alone discharges 1,450,828,800m³ of water. Closer to the canal, the Amazon River discharges as much water as a ship locking does every ½ second. Admittedly, the Amazon River is by far the largest river in terms of discharge. If my math is right, the Panama Canal uses less water than a small metropolis.
- mikeash 10y ago
  I think it's important to point out that "uses water" here means "temporarily restrains water on its natural way to the ocean." This water isn't being pulled out of storage and dumped in the ocean, it's precipitation that would be going into the ocean anyway. Using it in the canal first could very well reduce the amount of fresh water that reaches the ocean, since retaining it would cause some evaporation loss. Although I'm sure that's completely insignificant either way.
  - Rexxar 10y ago
    The artificial lake created by the canal (Gatun Lake) has a surface of 425km² so indeed we can effectively say that some water has been restrained on its natural way to the ocean.
- hga 10y ago
  I just happened to be checking my water bill online earlier today, and it pointed me to the company's water quality evaluation (http://www.amwater.com/twq/JP_twq.pdf http://www.amwater.com/twq/JP_twq.pdf), which listed daily water supplied as its first statistic, about 48,800m³. We're a rather small metropolis, ~50K residents of the city proper, not all of whom are on the water system, plus the system supplies to some neighboring cities, 270K daytime population for the city itself, a lot of industry, at least some of which is water hungry (bottling beverages rather requires that...). A city/metro area 10 times as big with comparable industry, which is still pretty small, would indeed about equal the water the canal puts to very good use, no waste I say. If you've ever been to the Canal Zone, you know it has absolutely no lack for water, heck, we've been doing jungle training there forever.
CPLX 10y ago
Though perhaps it will take a second of inductive thinking to understand why, it's worth noting that all fresh water that exists on the planet is heading for the ocean unless it's frozen permanently or evaporates first.
- FreeFull 10y ago
  Not necessarily, for example the southern part of the Nile flows into inland lakes, which don't have any outlets.
  - deleted 10y ago
    [deleted]
- usrusr 10y ago
  Locks move a certain amount of water downstream with each operation, proportional to height and supported ship dimension. They are essentially hydro-powered. Water savings basins help increase the number of lock operations per flow, but they are expensive in construction, land use and leakage/evaporation. Usually, canal operators have to carefully balance ship throughput with available flow to not drain their highest level, investing in savings basins if necessary. The Panama canal is using a large natural lake as the highest level, which means that overutilization of the available flow would not be immediately noticeable. In this situation, it is not at all unreasonable to be concerned that planners might be a bit too optimistic in terms of flow available/savings basins required or operators in terms of flow available/throughput sustainable. It would be a shame to drain a lake just to get stuff from China to New York a tiny little bit cheaper than it already is.
  - CPLX 10y ago
    > It would be a shame to drain a lake just to get stuff from China to New York a tiny little bit cheaper than it already is. Perhaps. There are a whole lot of lakes in the world, and only one shortcut between the Atlantic and Pacific oceans.
    - 10y ago
Animats 10y ago
In the 1960s and 1970s, a ship mounted nuclear reactor was used to reduce water consumption.[1] [1] https://en.wikipedia.org/wiki/MH-1A https://en.wikipedia.org/wiki/MH-1A

It is really disturbing to look at an article like this and not see a single mention of the HUGE amount of fresh water being dumped into the ocean in order for these locks to function.

fennecfoxen 10y ago

As an interested party, could you indicate some decent, accessible resources on the topic? A casual Google search for things like 'panama canal fresh water' isn't turning up much that looks particularly authoritative or comprehensive.

timthelion 10y ago
https://en.wikipedia.org/wiki/Panama_Canal#Water_issues https://en.wikipedia.org/wiki/Panama_Canal#Water_issues
- fennecfoxen 10y ago
  > https://en.wikipedia.org/wiki/Panama_Canal#Water_issues https://en.wikipedia.org/wiki/Panama_Canal#Water_issues That's written from the perspective of 'water shortages during the dry season are one reason they built new locks, which can reuse water'. It doesn't begin to address any impact on the oceans.

quantumhobbit 10y ago

Presumably the old locks were dumping slightly less huge amount of fresh water. Has the ratio of fresh water to cargo improved or gotten worse with upgrade? Maybe there is an opportunity to make use of osmotic power https://en.m.wikipedia.org/wiki/Osmotic_power https://en.m.wikipedia.org/wiki/Osmotic_power with the locks.

dalke 10y ago
The new locks use water saving basins. https://en.wikipedia.org/wiki/Panama_Canal_expansion_project#Water_saving_basins https://en.wikipedia.org/wiki/Panama_Canal_expansion_project... According to http://www.marinelink.com/news/watersaving-panama-canal404727.aspx http://www.marinelink.com/news/watersaving-panama-canal40472... : > And each [pond] utilizes state-of-the art technology which allows the Canal to reuse 60 percent of the water used per lockage, saving 7 percent more than the existing locks do. Also, the current system requires no power, except to open and close valves. It is expensive to pump water uphill, because water is heavy.

dublinben 10y ago

Luckily fresh water is a renewable resource.

onion2k 10y ago

If the canal weren't there then the rain water that fills the lake that supplies the locks would just run in to the ocean anyway. The only difference the canal makes is when the water gets to the ocean - it gets stored in a lake for a while first. Does that really have an impact? Why?

chiph 10y ago

The new locks have nine water re-utilization basins to minimize lost water. Not because it's potable, but because if the lakes run dry, commerce stops.

jcranmer 10y ago

A single downward lock cycle uses 100,000m³. About 35-40 ships per day transit the canal, so a single day wastes about 4,000,000m³ of water. The Mississippi River discharges about 17,000m³ a second. Each day, that river alone discharges 1,450,828,800m³ of water. Closer to the canal, the Amazon River discharges as much water as a ship locking does every ½ second. Admittedly, the Amazon River is by far the largest river in terms of discharge. If my math is right, the Panama Canal uses less water than a small metropolis.

mikeash 10y ago
I think it's important to point out that "uses water" here means "temporarily restrains water on its natural way to the ocean." This water isn't being pulled out of storage and dumped in the ocean, it's precipitation that would be going into the ocean anyway. Using it in the canal first could very well reduce the amount of fresh water that reaches the ocean, since retaining it would cause some evaporation loss. Although I'm sure that's completely insignificant either way.
- Rexxar 10y ago
  The artificial lake created by the canal (Gatun Lake) has a surface of 425km² so indeed we can effectively say that some water has been restrained on its natural way to the ocean.
hga 10y ago
I just happened to be checking my water bill online earlier today, and it pointed me to the company's water quality evaluation (http://www.amwater.com/twq/JP_twq.pdf http://www.amwater.com/twq/JP_twq.pdf), which listed daily water supplied as its first statistic, about 48,800m³. We're a rather small metropolis, ~50K residents of the city proper, not all of whom are on the water system, plus the system supplies to some neighboring cities, 270K daytime population for the city itself, a lot of industry, at least some of which is water hungry (bottling beverages rather requires that...). A city/metro area 10 times as big with comparable industry, which is still pretty small, would indeed about equal the water the canal puts to very good use, no waste I say. If you've ever been to the Canal Zone, you know it has absolutely no lack for water, heck, we've been doing jungle training there forever.

CPLX 10y ago

Though perhaps it will take a second of inductive thinking to understand why, it's worth noting that all fresh water that exists on the planet is heading for the ocean unless it's frozen permanently or evaporates first.

FreeFull 10y ago
Not necessarily, for example the southern part of the Nile flows into inland lakes, which don't have any outlets.
- deleted 10y ago
  [deleted]
usrusr 10y ago
Locks move a certain amount of water downstream with each operation, proportional to height and supported ship dimension. They are essentially hydro-powered. Water savings basins help increase the number of lock operations per flow, but they are expensive in construction, land use and leakage/evaporation. Usually, canal operators have to carefully balance ship throughput with available flow to not drain their highest level, investing in savings basins if necessary. The Panama canal is using a large natural lake as the highest level, which means that overutilization of the available flow would not be immediately noticeable. In this situation, it is not at all unreasonable to be concerned that planners might be a bit too optimistic in terms of flow available/savings basins required or operators in terms of flow available/throughput sustainable. It would be a shame to drain a lake just to get stuff from China to New York a tiny little bit cheaper than it already is.
- CPLX 10y ago
  > It would be a shame to drain a lake just to get stuff from China to New York a tiny little bit cheaper than it already is. Perhaps. There are a whole lot of lakes in the world, and only one shortcut between the Atlantic and Pacific oceans.
  - 10y ago

Animats 10y ago

In the 1960s and 1970s, a ship mounted nuclear reactor was used to reduce water consumption.[1] [1] https://en.wikipedia.org/wiki/MH-1A https://en.wikipedia.org/wiki/MH-1A